The pilot was certified in accordance with the existing regulations; however, he was relatively inexperienced with seaplane operations and river landings and had not landed at Ferguson's Cabin in the past. Although he was aware of the implications of landing in the bay, the pilot elected to land closer to the cabin rather than in the main channel of the river. Because the landing area in the bay was relatively short and was bordered with trees and a rising shoreline, precision flying was required to prevent running into the far shore. The decision to land in the bay increased the risk associated with the landing and left no margin for error. It was likely that the aircraft touched down in a nose-low attitude or that it pitched sufficiently nose down after touchdown that the left float dug in. This would have generated high water drag on the float, which would have rapidly increased the pitch-down tendency. Although the wind could have been a factor, its contribution to the occurrence could not be determined. The pilot was unable to regain positive control of the aircraft before it cartwheeled and sank. The primary route for emergency escape from this type of aircraft is through the two main cabin doors. Use of the cabin doors was described during the pre-flight passenger briefing; however, this briefing presumed that, in the event of an emergency, the aircraft would be in the upright position and above water. Despite having received no immobilizing injuries, the survivors were unable to locate the cabin door handles in the inverted aircraft, delaying their escape from the submerged cabin. As well, the aircraft had sustained impact damage that may have prevented the normal opening of the cabin doors, even if the door handles had been rotated sufficiently to unlatch the doors. The broken window in the left door was likely the only recognized and available means of exit, and all four occupants could not have exited through the window simultaneously. The amount of time each individual would have to remain conscious underwater would have depended on the order in which they were able to discover and gain access to the window. The egress actions of the two decedents could not be determined. However, the time necessary for them to release their lap belts, orient themselves, determine that the broken window offered an opportunity for escape, and then squeeze through the window may have exceeded their time of useful consciousness. None of the occupants was wearing a life preserver, and the ability of the survivors to escape through the narrow window opening in the left cabin door may have been impeded had they been wearing any type of life preserver. The life preservers were stowed in unreachable areas and, therefore, they were not available to the occupants for transport to and donning at the surface. Defences in place to assist occupants in escaping from submerged seaplanes include restraint systems to reduce impact injuries and pre-flight safety briefings and safety-feature cards, which help to prepare them for the possibility of an underwater emergency exit. There are no additional requirements to make seaplane egress more achievable in emergency conditions. The actions necessary to egress a submerged seaplane are demanding at best, and the risks of entrapment and drowning increase if the occupants are not provided with the appropriate information. In this accident, the pre-flight briefing or the safety-feature cards did not mentally prepare the passengers. Their survival opportunities were further decreased because they were unable to open the main exits after the cabin submerged. There are hundreds of seaplanes operating seasonally in Canada, in both private and commercial service, and this and previous accidents indicate that a high percentage of seaplane occupants continue to survive a water impact only to drown as the consequence of being trapped inside the submerged cabin. The risk of drowning inside the aircraft after surviving the accident remains high, and more defences are needed to mitigate that risk.Analysis The pilot was certified in accordance with the existing regulations; however, he was relatively inexperienced with seaplane operations and river landings and had not landed at Ferguson's Cabin in the past. Although he was aware of the implications of landing in the bay, the pilot elected to land closer to the cabin rather than in the main channel of the river. Because the landing area in the bay was relatively short and was bordered with trees and a rising shoreline, precision flying was required to prevent running into the far shore. The decision to land in the bay increased the risk associated with the landing and left no margin for error. It was likely that the aircraft touched down in a nose-low attitude or that it pitched sufficiently nose down after touchdown that the left float dug in. This would have generated high water drag on the float, which would have rapidly increased the pitch-down tendency. Although the wind could have been a factor, its contribution to the occurrence could not be determined. The pilot was unable to regain positive control of the aircraft before it cartwheeled and sank. The primary route for emergency escape from this type of aircraft is through the two main cabin doors. Use of the cabin doors was described during the pre-flight passenger briefing; however, this briefing presumed that, in the event of an emergency, the aircraft would be in the upright position and above water. Despite having received no immobilizing injuries, the survivors were unable to locate the cabin door handles in the inverted aircraft, delaying their escape from the submerged cabin. As well, the aircraft had sustained impact damage that may have prevented the normal opening of the cabin doors, even if the door handles had been rotated sufficiently to unlatch the doors. The broken window in the left door was likely the only recognized and available means of exit, and all four occupants could not have exited through the window simultaneously. The amount of time each individual would have to remain conscious underwater would have depended on the order in which they were able to discover and gain access to the window. The egress actions of the two decedents could not be determined. However, the time necessary for them to release their lap belts, orient themselves, determine that the broken window offered an opportunity for escape, and then squeeze through the window may have exceeded their time of useful consciousness. None of the occupants was wearing a life preserver, and the ability of the survivors to escape through the narrow window opening in the left cabin door may have been impeded had they been wearing any type of life preserver. The life preservers were stowed in unreachable areas and, therefore, they were not available to the occupants for transport to and donning at the surface. Defences in place to assist occupants in escaping from submerged seaplanes include restraint systems to reduce impact injuries and pre-flight safety briefings and safety-feature cards, which help to prepare them for the possibility of an underwater emergency exit. There are no additional requirements to make seaplane egress more achievable in emergency conditions. The actions necessary to egress a submerged seaplane are demanding at best, and the risks of entrapment and drowning increase if the occupants are not provided with the appropriate information. In this accident, the pre-flight briefing or the safety-feature cards did not mentally prepare the passengers. Their survival opportunities were further decreased because they were unable to open the main exits after the cabin submerged. There are hundreds of seaplanes operating seasonally in Canada, in both private and commercial service, and this and previous accidents indicate that a high percentage of seaplane occupants continue to survive a water impact only to drown as the consequence of being trapped inside the submerged cabin. The risk of drowning inside the aircraft after surviving the accident remains high, and more defences are needed to mitigate that risk. For undetermined reasons, the aircraft contacted the water in a nose-low attitude on landing or entered a nose-low attitude shortly after touchdown. As a result, the left float dug in and the aircraft cartwheeled. The survivors were unable to locate the interior door handles after the seaplane became inverted and submerged in the water, thus preventing them from using the doors as emergency exits.Findings as to Causes and Contributing Factors For undetermined reasons, the aircraft contacted the water in a nose-low attitude on landing or entered a nose-low attitude shortly after touchdown. As a result, the left float dug in and the aircraft cartwheeled. The survivors were unable to locate the interior door handles after the seaplane became inverted and submerged in the water, thus preventing them from using the doors as emergency exits. Seaplane passengers who do not receive underwater egress information during a pre-flight briefing or on a safety-feature card may not be mentally prepared for an emergency exit from a submerged aircraft. The life preservers were not stowed in an area that made them easily accessible to the occupants. The pilot and front passenger were not wearing their available shoulder harnesses during the landing, as required by regulation. The baggage was not secured in the baggage compartment, which increases the risk of injury to the occupants during the crash or of impeding their exit from the aircraft. The weight of the baggage in cargo area 1 probably exceeded the compartment's structural limit and increased the probability of damage to the aircraft.Findings as to Risk Seaplane passengers who do not receive underwater egress information during a pre-flight briefing or on a safety-feature card may not be mentally prepared for an emergency exit from a submerged aircraft. The life preservers were not stowed in an area that made them easily accessible to the occupants. The pilot and front passenger were not wearing their available shoulder harnesses during the landing, as required by regulation. The baggage was not secured in the baggage compartment, which increases the risk of injury to the occupants during the crash or of impeding their exit from the aircraft. The weight of the baggage in cargo area 1 probably exceeded the compartment's structural limit and increased the probability of damage to the aircraft. On 13September2004, the TSB issued an Aviation Safety Advisory (A040044) to Transport Canada (TC), with a copy to the National Transportation Safety Board (NTSB), the Federal Aviation Administration (FAA) and the Cessna Aircraft Company. The advisory suggested that TC consider additional methods to facilitate rapid emergency exits from seaplanes in the event that the cabin becomes submerged. TC responded to the Advisory on 03November2004. TC has published another article for the Aviation Safety Letter, and plans to prepare new or revised safety promotional material to address the advisory's subject matter. It also intends to develop an emergency procedures training program for its inspectors and to review information on seaplane operations to determine the best method to reach 703operators with information on conducting thorough pre-flight briefings, including underwater egress and situational awareness. TC also advised that the safety-feature card/placard information required under Section703.39 of CARs is deemed appropriate for seaplane operations and that it would be impractical to require additional egress information on seaplane safety-feature cards. TC also stated that the suggestion of jettisonable doors or large frangible or pop-out windows that would facilitate emergency exits is within the authority of the state of design authority and that it will not take any action relating to this issue. On 13September2004, the TSB issued an Aviation Safety Information Letter(A040046) toTC, with a copy to the NTSB, the FAA and the Cessna Aircraft Company, regarding passenger briefings and safety-feature cards in seaplane operations. TC responded to the information letter on 03November2004. As stated in its response to the Safety Advisory noted above, TC indicated it is planning to publish another article for the Aviation Safety Letter, prepare new or revised safety promotional material, and develop an emergency procedures training program for its inspectors. It also intends to review information on seaplane operations to determine the best method to reach 703seaplane operators with information on conducting thorough pre-flight briefings. In addition, the response restated that the safety-feature card/placard information required under Section703.39 of CARs is deemed appropriate for seaplane operations and that it would be impractical to require additional egress information on seaplane safety-feature cards.Safety Action Taken On 13September2004, the TSB issued an Aviation Safety Advisory (A040044) to Transport Canada (TC), with a copy to the National Transportation Safety Board (NTSB), the Federal Aviation Administration (FAA) and the Cessna Aircraft Company. The advisory suggested that TC consider additional methods to facilitate rapid emergency exits from seaplanes in the event that the cabin becomes submerged. TC responded to the Advisory on 03November2004. TC has published another article for the Aviation Safety Letter, and plans to prepare new or revised safety promotional material to address the advisory's subject matter. It also intends to develop an emergency procedures training program for its inspectors and to review information on seaplane operations to determine the best method to reach 703operators with information on conducting thorough pre-flight briefings, including underwater egress and situational awareness. TC also advised that the safety-feature card/placard information required under Section703.39 of CARs is deemed appropriate for seaplane operations and that it would be impractical to require additional egress information on seaplane safety-feature cards. TC also stated that the suggestion of jettisonable doors or large frangible or pop-out windows that would facilitate emergency exits is within the authority of the state of design authority and that it will not take any action relating to this issue. On 13September2004, the TSB issued an Aviation Safety Information Letter(A040046) toTC, with a copy to the NTSB, the FAA and the Cessna Aircraft Company, regarding passenger briefings and safety-feature cards in seaplane operations. TC responded to the information letter on 03November2004. As stated in its response to the Safety Advisory noted above, TC indicated it is planning to publish another article for the Aviation Safety Letter, prepare new or revised safety promotional material, and develop an emergency procedures training program for its inspectors. It also intends to review information on seaplane operations to determine the best method to reach 703seaplane operators with information on conducting thorough pre-flight briefings. In addition, the response restated that the safety-feature card/placard information required under Section703.39 of CARs is deemed appropriate for seaplane operations and that it would be impractical to require additional egress information on seaplane safety-feature cards. Safety Concern Risk of Drowning in Survivable Seaplane Accidents Based on historical data, occupants of submerged seaplanes who survive the accident continue to be at risk of drowning inside the aircraft. Existing defences against drowning in such circumstances may not be adequate. In light of the potential loss of life associated with seaplane accidents on water, the TSB is concerned that seaplane occupants may not be adequately prepared to escape the aircraft after it becomes submerged. The Board is also concerned that seaplanes may not be optimally designed to allow easy occupant egress while under water.